Polymeric materials may be processed to form articles having a number of different shapes and sizes. Conventional polymer processing techniques include injection molding, extrusion, and blow molding. Injection molding generally involves injecting molten plastic into a mold cavity, cooling the molten plastic, and opening the mold to produce an injected molded article having a shape similar to the mold cavity.
In some cases, it may be desirable to adhere a substrate material to an exterior surface of a polymeric article. Such substrates may be used to enhance the appearance of the article and/or to improve properties (e.g., stiffness) of the article. Exemplary substrate materials include films and fabrics.
In-mold decorating techniques produce molded articles which include a substrate adhered to a surface of the article. These techniques typically involve placing a substrate within the mold cavity so that molten polymer injected into the mold forces the substrate material against a mold wall. When the polymer cools, it adheres to the substrate material. The mold may be opened to produce a molded article having a substrate on its exterior surface.
Conventional in-mold decorating techniques typically involve injecting molten polymer at high temperatures and pressures into the mold to ensure adequate filling and/or sufficient adherence of the substrate to the plastic molded article. However, these conditions may damage certain types of substrates. For example, film substrates may shrink or crack as a result of high temperatures. Furthermore, when fabric substrates are used, a barrier layer may be required to prevent polymer from bleeding through the fabric as a result of high injection pressures. The barrier layer may add to the cost of producing the injection molded article and may reduce the adherence of the fabric to the polymeric material.
Accordingly, there is a need for improved in-mold decorated articles and a method to produce the articles.